slixmpp/sleekxmpp/xmlstream/matcher/xpath.py
2012-06-19 09:47:31 -07:00

86 lines
2.8 KiB
Python

# -*- coding: utf-8 -*-
"""
sleekxmpp.xmlstream.matcher.xpath
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Part of SleekXMPP: The Sleek XMPP Library
:copyright: (c) 2011 Nathanael C. Fritz
:license: MIT, see LICENSE for more details
"""
from sleekxmpp.xmlstream.stanzabase import ET
from sleekxmpp.xmlstream.matcher.base import MatcherBase
# Flag indicating if the builtin XPath matcher should be used, which
# uses namespaces, or a custom matcher that ignores namespaces.
# Changing this will affect ALL XPath matchers.
IGNORE_NS = False
class MatchXPath(MatcherBase):
"""
The XPath matcher selects stanzas whose XML contents matches a given
XPath expression.
.. warning::
Using this matcher may not produce expected behavior when using
attribute selectors. For Python 2.6 and 3.1, the ElementTree
:meth:`~xml.etree.ElementTree.Element.find()` method does
not support the use of attribute selectors. If you need to
support Python 2.6 or 3.1, it might be more useful to use a
:class:`~sleekxmpp.xmlstream.matcher.stanzapath.StanzaPath` matcher.
If the value of :data:`IGNORE_NS` is set to ``True``, then XPath
expressions will be matched without using namespaces.
"""
def match(self, xml):
"""
Compare a stanza's XML contents to an XPath expression.
If the value of :data:`IGNORE_NS` is set to ``True``, then XPath
expressions will be matched without using namespaces.
.. warning::
In Python 2.6 and 3.1 the ElementTree
:meth:`~xml.etree.ElementTree.Element.find()` method does not
support attribute selectors in the XPath expression.
:param xml: The :class:`~sleekxmpp.xmlstream.stanzabase.ElementBase`
stanza to compare against.
"""
if hasattr(xml, 'xml'):
xml = xml.xml
x = ET.Element('x')
x.append(xml)
if not IGNORE_NS:
# Use builtin, namespace respecting, XPath matcher.
if x.find(self._criteria) is not None:
return True
return False
else:
# Remove namespaces from the XPath expression.
criteria = []
for ns_block in self._criteria.split('{'):
criteria.extend(ns_block.split('}')[-1].split('/'))
# Walk the XPath expression.
xml = x
for tag in criteria:
if not tag:
# Skip empty tag name artifacts from the cleanup phase.
continue
children = [c.tag.split('}')[-1] for c in xml]
try:
index = children.index(tag)
except ValueError:
return False
xml = list(xml)[index]
return True